David Cameron has denied the arrest of Sinn Fein leader Gerry Adams was "politically motivated".

Mr Adams was arrested on Wednesday night over the execution of mother-of-10 Jean McConville. He has always denied being involved in her killing but former IRA members have claimed he directed the murder.

Sinn Fein deputy leader Mary Lou McDonald said the arrest was "politically motivated" and designed to damage the party and its president.

Asked if the arrest was “politically motivated”, the Prime Minister’s official spokesman said: “This is entirely and rightly so an independent police matter.

“There has been an ongoing investigation into this for a period of time now as is a well known matter of public record.”

The spokesman denied to say when Number 10 was informed of the arrest or impending arrest. He said: “Details of the police investigation and how the PSNI (Police Service of Northern Ireland) is going about that – that is a matter of them.”

The spokesman also said that Mr Cameron last met Mr Adams in June 2011, when the Prime Minister visited the Northern Ireland assembly.

Asked if the arrest had any repercussions for the peace protest, the spokesman replied: “I would distinguish between what is a matter for the police in terms of the investigation into what was an appalling crime, and separately the work that the British and Irish governments do in support of the Northern Ireland assembly and work in Northern Ireland.”

No one has ever been charged with the murder of Mrs McConville. But after years without progress in the criminal investigation there have been a series of arrests in recent weeks.

A veteran republican - 77-year-old Ivor Bell - was charged in March with aiding and abetting the murder. Five other people have been detained and questioned.

The recent police activity has come in the wake of a decision by a court in the United States that compelled a university in Boston to hand over to the Police Service of Northern Ireland recorded interviews with republicans about Mrs McConville's murder.

Boston College interviewed a number of former paramilitaries about the Troubles on the understanding transcripts would not be published until after their deaths - but that undertaking was rendered ineffective when the court last year ordered that tapes that contained claims about the killing be given to detectives.

In the wake of the recent developments, Mr Adams, who has always denied membership of the IRA, said in March he would be available to meet with detectives if they wished to speak with him.

Mr Adams, 65, a former MP for West Belfast and now a representative for Co Louth in the Irish Dail, presented himself at Antrim police station by prior arrangement with officers.

He issued a statement minutes after the PSNI announced an arrest had been made.

"While I have concerns about the timing, I am voluntarily meeting with the PSNI this evening," he said last night, questioning why police chose to interview him in the run up to an election.

"As a republican leader I have never shirked my responsibility to build the peace. This includes dealing with the difficult issue of victims and their families. Insofar as it is possible I have worked to bring closure to victims and their families who have contacted me. Even though they may not agree, this includes the family of Jean McConville.

"I believe that the killing of Jean McConville and the secret burial of her body was wrong and a grievous injustice to her and her family. Well publicised, malicious allegations have been made against me. I reject these.

"While I have never disassociated myself from the IRA and I never will, I am innocent of any part in the abduction, killing or burial of Mrs McConville."

Ms McDonald later said: "Gerry Adams is right to confront this issue. There has been a concerted and malicious effort to link Gerry Adams to this case for some considerable time.

"He has consistently and forthrightly rejected any suggestion that he had any part in what happened to Jean McConville 42 years ago or that he has any information about these dreadful events.

"I believe the timing of this latest decision by the PSNI is politically motivated and designed to damage Gerry Adams and Sinn Fein."

She said the party believes dealing with the past is best addressed through an "independent, international, truth recovery process" and supports the latest talks led by US diplomat Dr Richard Haass.

A PSNI spokesman said on Wednesday: "Detectives from the serious crime branch investigating the abduction and murder of Jean McConville in 1972 have arrested a 65-year-old man in Antrim. The suspect is currently being interviewed by detectives at the serious crime suite in Antrim police station."

Mrs McConville, a 37-year-old widow, was dragged away from her children in her home in the Divis flats, west Belfast, by an IRA gang of up to 12 men and women after being accused of passing information to the British Army in the city.

She was murdered and secretly buried, becoming one of the so-called Disappeared victims of the Troubles.

An investigation later carried out by the Northern Ireland Police Ombudsman rejected the claims that she was an informer.

She was shot in the back of the head and buried 50 miles from her home. Clearly embarrassed by the killing, the IRA did not officially admit responsibility for the murder until 1999 when information was passed to police in the Irish Republic.

It was not until August 2003 that her remains were found on Shelling Hill beach, Co Louth.